Tuesday, September 29, 2009

More H1N1 flu controversy: vitamin D deficiency, being elderly, and the seasonal vaccine

Here are a few questions that have been asked of me in response to my first H1N1 post, or at work in the process dealing with other healthcare providers who are concerned about their well-being during the flu this season. I’m not an expert in H1N1, and below are simply my opinions on the issues raised. I think discussion is important and you can take what you will from it.

1. Is Vitamin D deficiency linked with H1N1?

According to the website of naturopath Dr. Mercola, being deficient in Vitamin D makes one susceptible to H1N1. He argues this by employing CDC data about recent deaths in chronically ill children. [ JI: I hope you will bear with me as I think this is an important idea, and it's worth re-hashing our discourse in this public forum]

The argument is as follows:

1. kids who are sick are more susceptible to getting sick! (i.e. kids with cerebral palsy are more likely to get very sick with H1N1)

2. kids who are chronically sick are vitamin D deficient

3. those who get H1N1 must be vitamin D deficient

Yes, the correlation may be there, but premise 3 does not follow from the axioms 1 &2.

As the article says, lots and lots and lots of children are Vitamin D deficient, and they don’t all have H1N1. Also, of those who have H1N1, not all are Vitamin D deficient [ok, this article does not demonstrate that ANY of the children who died were in fact Vitamin D deficient, it just says it is likely]. In addition, no mechanism for Vitamin D and susceptibility for flu is proposed.

Compound this with the fact that the website sells Vitamin D  (hello, conflict of interest!) and I just don’t buy it. This is where I feel the Internet can be a dangerous place. I am lucky enough to have been through the rigours of undergrad science and medical school, having had critical thinking beaten into me.  I think lots of non-allopathic practitioners and health reporters (including those with the CBC) are lacking in this area. Education in language and logic, as well as scientific reasoning, should be necessary for anyone trying to draw scientific conclusions or to interpret technical literature.

That said, in my part of the world, people don’t get enough Vitamin D from the sun between October and April. Talk to your doctor and see if you need Vitamin D for bone health.

2. Are older  people already exposed to H1N1, and thus resistant?

Yes and no. People born before 1950 may have encountered, carried, or been actively infected with a similar strain of the flu, according to a CDC report in May 2009 (MD Consult news). Past exposure means a potential for current resistance. But not everyone over a certain age will have been exposed, and even if they were, it is not certain that they will have maintained any degree of resistance. On an individual level, this fact should not affect whether a person get a flu vaccine. I think it’s best to consider this piece of news as an interesting explanation for the lower-than-expected rate of H1N1 in the senior population.

3.  Does the seasonal flu vaccine interfere with the H1N1 vaccine’s efficacy?

Maybe? So far, there isn’t a lot of data on this. Preliminary testing reveals there may be some interaction. Quebec has taken a hardline stance on this, intending to offer only the H1N1 shot, but I think the safest thing is to wait for more information. Lots of medications are known to interact, and in many cases, staggering the dosing (i.e. leaving enough time between each medication) can be helpful for avoiding/reducing the degree of interaction. Seasonal flu shots are due in October, and H1N1 vaccines won’t be available until November. Seasonal flu is not a nice beast either. Just because then H1N1 strain is getting all the media attention, it doesn’t mean the seasonal flu is going to forget to infect us.

4. Are vaccines safe? Aren’t they full of Mercury and other toxins? Don’t they cause autism?

I hear these questions a lot. I’m going to address it more thoroughly in a separate post, because I think it deserves a lengthy discussion. Stay tuned!

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